Generally, horizontally continuously cast aluminum alloy rods are manufactured through casting. Specifically, molten aluminum alloy is cast into elongated ingots assuming the form of a circular pillar, a square pillar or a hollow pillar. The manufacturing method will be described below.
First, raw material for aluminum alloy is charged into a melting/holding furnace to produce molten aluminum alloy. Then, aluminum oxide and hydrogen gas are removed from the molten aluminum alloy by use of a molten-metal treatment apparatus. Subsequently, the treated molten aluminum alloy is supplied to a horizontally continuously casting apparatus to thereby manufacture horizontally continuously cast aluminum alloy rods. Next, the horizontally continuously cast aluminum alloy rods are cut to a predetermined length and subjected to subsequent processes (machining and heat treatment). Refer to, for example, JP-A SHO 63-104751 and JP-A SHO 62-89551.
Notably, molten aluminum alloy is transferred from the melting/holding furnace to the molten-metal treatment apparatus by use of a ladling apparatus having a ladle or by use of a heat-resistant chute.
Cut, horizontally continuously cast, aluminum alloy rods are bundled and then transferred by use of a crane or forklift.
However, an as-cast ingot (continuously cast aluminum alloy rod) has a heterogeneous microstructure, typified by an inverse segregation layer, formed in a surface thereof. Since such a heterogeneous microstructure causes cracking or the like in the course of plastic working that uses a continuously cast aluminum alloy rod as raw material, a production process for producing continuously cast aluminum alloy rods needs to include a peeling process for removing a portion of heterogeneous microstructure through cutting.
Thus, conventionally, obtained continuously cast aluminum alloy rods are fed to a peeling apparatus for removing their respective casting surface portions (also called “skin”).
Furthermore, the continuously cast aluminum alloy rods that have undergone removal of their respective casting surface portions (skin portions) are subjected to quality inspection in a nondestructive inspection process, which combines surface inspection performed by an operator's visual inspection or by use of eddy current, and internal inspection performed by use of ultrasonic waves or X-rays (refer to, for example, “Ultrasonic Technology Handbook,” The Nikkan Kogyo Shimbun, Ltd., 30 Dec. 1985, pp. 721-737).
Conventionally, in the manufacture of horizontally continuously cast aluminum alloy rods, the above-mentioned processes have been performed in a batch-like fashion. The manufacture involves periodic supply of raw material, bundling for conveyance and release from a bundled condition, for example. As a result, horizontally continuously cast aluminum alloy rods cannot be manufactured efficiently over a long period of time.
Implementation of a through, continuous process must solve the problems on how aluminum alloy is supplied continuously over a long period of time in a consistent manner and how horizontally continuously cast aluminum alloy rods are conveyed smoothly between processes.
Therefore, mere interconnection of apparatus has encountered difficulty in implementing a through, continuous process.
However, conventionally, since continuously cast aluminum alloy rods have not been continuously fed to a peeling apparatus, the peeling process has encountered difficulty in removing casting surface portions with high productivity.
Since production processes and an inspection process undergo their separate batch processes, cooperation between adjacent processes is insufficient, and feedback of inspection results to the production processes involves a time lag. As a result, continuous production of continuously cast aluminum alloy rods of consistent quality has failed to attain.
In view of the foregoing, an object of the present invention is to provide a method and equipment for manufacturing horizontally continuously cast aluminum alloy rods capable of continuously manufacturing horizontally continuously cast aluminum alloy rods efficiently over a long period of time, as well as horizontally continuously cast aluminum alloy rods manufactured by the method or equipment.